Abstract
1. The influence of the presence of α-tocophergl acetate (α-TAc) in the diet of rats on the latent ATP-ase activity, and the dinitrophenol (DNP)-induced activity has been investigated in isolated liver mitochondria.
2. The findings that α-TAc caused an increase in the latent activity of the enzyme but an inhibition of the degree of DNP-induced activity was investigated secondarily using whole rat liver homogenates and adding α-TAc in vitro.
3. α-TAc, when added to homogenate system, activates the latent ATP-ase activity, and inhibits the degree of DNP-stimulated activity, thus confirming the findings in isolated mitochondrial experiments.
4. It is concluded that α-TAc has at least two functions which result in paradoxical effects (a), in which ATP-ase is stimulated indirectly, possibly by a removal of free thiol groups which are inhibitory to ATP-ase, and (b) in which DNP is inhibited by complexing or by removal by some other means from the active bond site.
